Do a custom build of podd documentation

  If the podd docs are built using the ROOT tagfile, then when the hcana
  docs are built using the podd tag file, doxygen crashes.  This commit
  adds building of the podd docs to the hcana doc building Makefile.  The
  podd docs are built without using the ROOT tagfile, so a sed hack is used
  to modify podd's Doxyfile.

.gitignore

@@ -40,6 +40,8 @@ config.log
 # Doxygen generated documentation directory
 docs/ROOT.tag
 docs/html
+docs/Doxyfile_podd
+docs/Doxygen_podd.tag
 
 # Examples directory
 examples/*.root

docs/Doxyfile

@@ -1310,8 +1310,8 @@ SKIP_FUNCTION_MACROS   = YES
 # If a tag file is not located in the directory in which doxygen
 # is run, you must also specify the path to the tagfile here.
 
-TAGFILES               = ../podd/docs/Doxygen.tag=../podddocs \
-                         ./ROOT.tag=https://root.cern.ch/doc/master
+TAGFILES               = Doxygen_podd.tag=../podddocs \
+                          ./ROOT.tag=https://root.cern.ch/doc/master
 
 # When a file name is specified after GENERATE_TAGFILE, doxygen will create
 # a tag file that is based on the input files it reads.

docs/Makefile

@@ -4,14 +4,27 @@ DOXYGEN_OUTPUT_DIRECTORY ?= .
 export DOXYGEN_OUTPUT_DIRECTORY
 export DOXYGEN_SOURCE_DIRECTORY := ..
 
+PODDDIR = ../podd/docs
+# THISDIR is location of this directory relative to the podd docs directory
+THISDIR = ../../docs
 
 all: doxygen
 
-doxygen: Doxyfile ROOT.tag
+doxygen: Doxyfile Doxygen_podd.tag ROOT.tag
 	doxygen
 
+Doxyfile_podd: $(PODDDIR)/Doxyfile
+	sed -e 's/^TAGFILES.*/TAGFILES = /;s|Doxygen.tag|$(THISDIR)/Doxygen_podd.tag|' $< > $@
+
+Doxygen_podd.tag: Doxyfile_podd
+	cd $(PODDDIR);doxygen $(THISDIR)/Doxyfile_podd
+
 ROOT.tag:
 	wget https://root.cern.ch/doc/master/ROOT.tag
 
 clean:
 	rm -r $(DOXYGEN_OUTPUT_DIRECTORY)/html
+	rm -r $(PODDDIR)/html
+	rm Doxyfile_podd
+	rm Doxygen_podd.tag
+